“It doesn’t make any difference what I eat. Weight problems just run in my family. It’s all genetic.” These are common excuses, but genetic research has just shot them down in flames.
Genes do influence our size and shape, but studies clearly show that if you change your diet and lifestyle, you can override hereditary effects to a great degree. Contrary to popular understanding, genes are not dictators, they are committees. They do not give orders; they make suggestions. You can counteract your fat genes and boost your thin genes.
We often think of genes as unchangeable because, when it comes to eye color or hair color, they really are decisive. If they call for blue eyes or brown hair, that’s it. But the genes that establish your size and shape are much more flexible. They need to be able to adjust your appetite and your calorie burning, depending on whether food is plentiful or not, and whether you are working hard or resting. Unlike eye or hair color, your body has to be able to change its composition from minute to minute, from day to day.
Although your chromosomes are extraordinarily complex, there are just five key gene...